Tech washed and serviced unit. Upon arrival customer explained a burnt smell they had smelled a while ago, office couldn’t send anyone out and reccomended vacuuming return. Customer has not smelt burnt smell but reccomended media filter to keep build up from returning. Tech also reccomended replacing UV bulb. Customer not interested. Unit is operating properly holding a delta T of 19. Customer requested another 24x24x1 be dropped off.